Bought a 3.5" DP, int WG, on TB. Tried to install

[crow]

it but the flange holes would not line up with my stock Garrett turbo. Tried to install it on another turbo but would not line up. Has anyone, here, ever run accross this problem. What did you do?
I went ahead and reamed out the holes a little and installed the pipe. I figured I had no other recourse. Charged to experience.
Have not had a chance to open her up but in city driving the GN runs great, smoother I think. It sounds good too.
BTW, I was told, b y the seller, that it might be a Hoffman or a Mease made pipe. He sdaid that was what he was told when he nbought it

 

[pacecarta]

if reaming was what it it needed to fit on your car ..it is what it is
the stock postion has so many ways to vary that its nearly imposible to say a pipe built to one car will fit all perfect , thats why gm used a ball flange down pipe .. lots o room for variations .
add that over the years the heat in the headers under boost causes the pipes to glow allowing the turbo mounting mounting flange to move and twist especially if it had force on it from the downpipe or the intercooler
add to that sagging motor mounts , sagging body mounts, the play in the header mounting bolts and you see where im going... with aftermarket if it goes in perfect the first time thats great but you should expect to have to do some tweaking ,
and then theres the thing about cost and oversees manufacturing that can take a part that did fit perfect and the end product is a diy kit ,
i had a 3.5 int gate pipe from a vendor (produced overseas dispite what they claim) that not only needed the holes reamed but the pipe to be cut and reworked to clear the frame and twisted to align with the exhaust, in the end it fit but the puck slop was another issue
dont forget that with any aftermarket dp the puck needs to be checked for coverage to ensure one it cover the hole and two that its not overlapping so much that it causes boost creep which is especially important on a pump gas only car that has to keep boost under 16psi. usually it requires porting of the turbo exhaust housing wastegate hole

 

[crow]

pacecarta, thanks for your reply. I'm not sure I understand you correctly. If Garrett makes a turbo with a bolt pattern, that pattern should be good forever. Would GM accept anything else? I shouldn't think so and the after market people too. How can you manufacture for an ever changing part?
Like I said, I used 2 stock turbos to compare bolt pattern on the DP. The DP's pattern did not line up with either turbo pattern in exactly the same way.
Now that you mentioned it, I'm now concerned about the puck slop. Puck slop being the int waste gate? I thought, while reaming, the reaming might affect the alignment of the puck. I asked a friend and he said I would know if it was misalligned as soon as the turbo kicked in. He says it will sound like a popcorn machine when the puck is misalligned.
Have not put the DP to the test yet. Got a speeding ticket night before last and was not even pulling any boost, hhh! That was dumb of me. Hate to pay fines. With all the new power I feel compelled to use it. There is now a monster inside me but I will control it. I'll focus on how my car changed from a loud growler to slightly less loud purrer. It is sweet!

 

[pacecarta]

the puck is larger than stock so it usually will cover an unported turbo wastegate hole

as for the holes that mount to the garrett housing agreed they should have fit without needing a drill , thats a manufacturing problem , problem i had besides the not fiting was that even with drilling the holes out two steps and reaming one to a slot the pipe fit the frame so poorly and the section leading to the converter wasnt parallel with the frame rails so it needed to be cut above the frame twisted and then rewelded

the slop becomes an issue if the puck is close to covering like on an already ported housing and then wiggles and doesnt cover , there goes your spoolup.
on the one i had it allowed exhaust to leak from the puck area enough that it was audible

 

[2toneNV]

pacecarta, thanks for your reply. I'm not sure I understand you correctly. If Garrett makes a turbo with a bolt pattern, that pattern should be good forever. Would GM accept anything else? I shouldn't think so and the after market people too. How can you manufacture for an ever changing part?
Like I said, I used 2 stock turbos to compare bolt pattern on the DP. The DP's pattern did not line up with either turbo pattern in exactly the same way.
Now that you mentioned it, I'm now concerned about the puck slop. Puck slop being the int waste gate? I thought, while reaming, the reaming might affect the alignment of the puck. I asked a friend and he said I would know if it was misalligned as soon as the turbo kicked in. He says it will sound like a popcorn machine when the puck is misalligned.
Have not put the DP to the test yet. Got a speeding ticket night before last and was not even pulling any boost, hhh! That was dumb of me. Hate to pay fines. With all the new power I feel compelled to use it. There is now a monster inside me but I will control it. I'll focus on how my car changed from a loud growler to slightly less loud purrer. It is sweet!

Crow, this is news to me. I had the downpipe on my stock turbo originally until I went to the Precision 67 turbo, but never had a problem with the flange alignment. I had the DP on the car with the stock motor mounts and then the HR motor mounts that are on the car now without any problem. Did the DP get delivered undamaged?

 

[crow]

Hello Craig, It arrived fine minus the bolts you told me about. The pipe was tight, that was to be expected but the holes would not line up inside the car to the turbo nor with the turbo out of the car clamped in a vice. Ooops, I meant vise. It was scary besides the bother, to find those holes not lining up. I even got another stock turbo and tried lining them up to no avail. In the end, reaming was the solution.
The pipe is on the car now and does not hit anything. It marries with the SS exhaust system nicely using the cut off pipe you provided.
I just came in from a test ride with my honey. She was pleased, impressed and put her stamp of approval on it. Steped on it and the car took off. Pegged the 85 speedo immediatly. She says the boost guage (the lights) was reading 10# when I took my foot off of it. I was worried about the puck. I know she had more left in the pedal. Therefore I'm hoping the puck lined up properly, Luuuucky! About the puck, not sure about how to find out if it is really ok. I guess I'll just have to open her up all the way someday soon. First, I have 130 MPH speedo to install, then I will check them both out, if I dare, hhhh!
Good thing I installed the pipe. Noticed my A-frame bushing is toast. I suspect this pipe will fry that bushing sooner than the stock DP. That is the price one pays I guess.
Thanks for taking an interest and replying.

 

[crow]

pacecarta, if you read 2toneWE4, you are up to date but one thing I omitted was, her identifying a high pitched sound. Unfortunatly, working around construction equipment has damaged my high end hearing and i could hear nothing. I told her the whine of the turbo should be more audible with the 2.5" exhaust, straight through mufflers and the 3.5 DP. However, if it was just the turbo and not gas escaping I cant tell yet. I will have someone more knowledgeable with me next time. I must say I did notice for the first time ever, spoolup lag of a couple of seconds. But once it spooled, holy cow!
Thanks for the input.